This application for MH 19506-18 is to continue our program of Psychobiological research in the Department of Psychiatry, Emory University School of Medicine. The School of Medicine wishes to support a comprehensive research program that is basic t the problems of brain function, behavior and mental health. The aim is to investigate the physiological and neuroendocrine bases of patterns of primate behavior. Major emphasis is given to the affectional and sexual responses and to the agonistic and aggressive responses. Three interrelated studies are proposed in a social primate, the cynomolgus monkey. Experiment I will use well-established behavioral techniques systematically to examine, for the first time in a male primate, how aromatizable and non-aromatizable androgens affect different types of male aggression. It will also investigate the social factors that elicit male aggression and how they influence the social bonding of the male-female pair. Experiment II will continue our studies on the behavioral effects in primates of medroxyprogesterone acetate (MPA), which is used clinically to treat violent aggression, particularly violence by men towards women. To understand the brain mechanisms involved, we will use high performance liquid chromatography, autoradiography and immunohistochemistry to study the uptake of androgens and progestins by the male primate brain, and to map the location of androgen- and progestin-target neurons and receptors. Experiment III is concerned with the metabolism of testosterone by brain, and specifically the role of its aromatization to estradiol in the male primate. Aromatization is important for sexual behavior in the male rat, and our preliminary findings with the aromatase inhibitor, Fadrozole, have indicated that this is also the case for the primate, an observation which has importance because of the clinical use of aromatase inhibitors in prostatic disease and cancer. We plan to develop these comparative behavioral and biochemical studies in male monkeys and to extend them to females.